“The Office” star Jenna Fischer shares triple positive breast cancer diagnosis. What you should know about the disease.

Jenna Fischer is cancer-free. The office Alum shared on Tuesday that she was diagnosed with stage 1 triple negative breast cancer on December 1, 2023 and has undergone a lumpectomy, chemotherapy and radiation over the past few months. The 50-year-old decided to keep her illness a secret until she completed treatment, but spoke out as part of Breast Cancer Awareness Month. “I’m making this announcement for two reasons,” Fischer wrote on Instagram. “Firstly, I’m willing to give up the wigs. Secondly, to ask you to get your annual mammograms.” She added: “You can also ask your doctor to calculate your breast cancer risk assessment score,” referencing the tool that resulted in that for fellow actress Olivia Munn was diagnosed with an aggressive form of breast cancer earlier this year.

Here's what you should know about Fischer's diagnosis and his cancer journey.

Fischer was diagnosed with a very early stage tumor

When Fischer went for her annual mammogram on October 1, 2023, she posted a selfie on Instagram with a quote from Michael Scott. “I have to deal with these ticking time bags ladies,” she wrote.

The results of this mammogram were inconclusive because she had dense breast tissue. According to the Centers for Disease Control and Prevention, about half of women have dense breast tissue, making it difficult to detect tumors. “Some women have what we call 'busier' breasts, where they have more things that make it harder for a screening radiologist to say, 'That's all clear,' based on the mammogram alone,” says Dr. Lynn Dengel, assistant professor of surgical oncology at the University of Virginia, previously told Yahoo Life. These women, including Fischer, often have to undergo additional tests to find out whether they have cancer. In Fischer's case, that meant a biopsy that led to a diagnosis of stage 1 triple-positive breast cancer two months later.

What is stage 1 triple positive breast cancer?

Triple-positive breast cancer is one of the more aggressive forms of the disease, but is also the most treatable variant, according to MD Anderson Cancer Center. When a tumor is “triple positive,” that means its growth is fueled by both the hormones estrogen and progesterone and a protein called human epidermal growth factor 2 (HER2). About 10% of all breast cancers are triple positive. These three fuel sources allow these tumors to grow faster than others, but also offer more treatment targets.

According to Memorial Sloan Kettering Cancer Center, Stage 1 is the earliest stage at which a cancer is considered invasive, meaning the tumor has grown into the surrounding breast tissue but is still confined to a small area. “Fortunately, my cancer was caught early and had not spread to my lymph nodes or the rest of my body,” Fischer wrote.

How is it treated?

If the disease is in stage 1, the main treatment is surgery to remove the tumor and part of the breast in which it is located, according to the American Cancer Society. This procedure is called a lumpectomy or partial mastectomy. Fischer underwent a lumpectomy, but because her cancer was a more aggressive, triple-positive tumor, she was also treated with 12 rounds of chemotherapy and three weeks of radiation “to make sure it doesn't come back,” she said. Fischer noted that she lost her hair during chemotherapy and wore hats and wigs with hair — “which my family affectionately called Wigats” — to help her maintain her privacy during her treatment.

Like many women diagnosed with hormone-related breast cancer, Fischer is still receiving additional treatments — infusions of Herceptin, a drug that blocks chemical signals that instruct HER2-positive cancer cells to grow, and tamoxifen, which blocks the cancer's ability to produce estrogen to use as fuel – to reduce the risk of cancer returning.

Fischer's prognosis is good

The actress shared that despite her ongoing preventative treatments, she is now “cancer free” and “feeling great.” According to the ACS, the outlook for women with stage 1 cancer is good, with a 5-year survival rate of 99%. But most people diagnosed with hormone-related cancer in the early stages of the disease will receive hormone therapies such as tamoxifen for several years.

Currently, Fischer's hair is growing back and she “wanted to post a photo of me in my patchy pixie looking happy and healthy to coincide with this big news,” she wrote.

Their message: “Consider this your kick in the ass” to get investigated

Fischer's diagnosis came as a result of an annual mammogram. The U.S. Preventive Services Task Force recommends that all women ages 40 to 74 get a mammogram every two years (the ACS says women should get the exam). everyone year between 45 and 54 years and “have the opportunity” to start at 40). However, 59% of respondents to a recent survey said they forgo recommended mammograms. Fischer almost skipped her last year. “Seeing women post photos of their mammogram appointments on Instagram made me want to create my own appointments,” she wrote. Fischer explained that her tumor was too small to be discovered during a physical exam. “If I had waited six months longer, things could have been much worse. It could have spread,” she said. “I'm so glad I did it. Consider this your kick in the butt to make it.”

Fischer also encouraged others to ask their doctors to calculate their breast cancer risk using the assessment tool, which Olivia Munn credits with saving her life after it led to her having more screening tests and her having an early one , but aggressive form of the disease was diagnosed. “I’m serious, call your doctor immediately” to ask about the tool, Fischer urged. While mammograms are only recommended for women age 40 and older, a doctor can use the risk assessment tool for patients age 35 and older who may be at higher risk of developing cancer due to factors such as their family history or previous illnesses. “In principle, every single woman needs to know her lifetime risk, even if there is no history of breast cancer in her family,” said Dr. Thaïs Aliabadi, Munn's own gynecologist and host of the SHE MD podcast, previously told Yahoo Life.